Yes,
you can set combination of Price(specific
variant combination ) in Odoo.

For e.g If I have a a product called Service Warranty and it has 3
types of Warranties ( Gold, Silver & Bronze) and each of these
variants has Different Service Period ( Say 1yr, 2yr, 3yr) all based
on amount paid by customer.

So what I did is I configured the Attributes and Attribute values on
the Product Form page. There will be now 9 variants of this product.
This because of the combinations of Types of Warranties and its
Service Periods.

Mmm, you mean the way that OpenERP 7 was dealing with variants?
My way is to create a pricing model (Write down all the variants vs. their prices) for the variant I'm dealing with, then play with attributes and prices to get what you need.